Milestones can be added to work orders, cases, and entitlements in Salesforce. Work orders are records that track service requests for customers. Cases are records that track customer issues or inquiries. Entitlements are units of customer support that specify what kind of support a customer is eligible for. You can use milestones to define the required steps and time limits for resolving work orders, cases, and entitlements.
Verified References: Milestones: Supported Objects